Geoduck clams (Panopea abrupta) dominate the biomass of benthic infaunal communities in many parts of Puget Sound, Washington, and support an important commercial fishery (Goodwin and Pease 1989). Since 1971, divers have commercially fished geoducks in Washington by individually extracting them from the substrate with high-pressure water jets. Various crab species, including the large and commercially important Dungeness crab (Cancer magister) are common on many geoduck beds north of Vashon Island in Puget Sound (unpublished Washington Department of Fish and Wildlife [WDFW] dive survey data). Recreational crab pot fishing also occurs on some of these geoduck beds, and some crab fishers have complained that their crab fishing success declines drastically following commercial geoduck harvest.

The objective of this study was to determine if there was a significant effect of commercial geoduck fishing on Dungeness crab fishing catch-per-unit-effort (CPUE). We sampled crabs using baited pots at one site before, during, and after commercial geoduck fishing. Concurrently, we sampled crabs at a nearby unfished site. Both sites were sampled 20 times over a period of 4.6 years. Specifically, we wanted to determine if significant changes in crab CPUE occurred following geoduck fishing in the treatment site, and if any such changes could be attributed to geoduck fishing.